1. Related Field
The present invention relates to a plasma-enhanced active laminar flow actuator system according to the preamble of claim 1 and one or more nano-engineered composite material layer(s), which serves as an aerodynamic surface during use, comprising components of the system according to claim 12.
2. Description of Related Art
An aerodynamic structure (e.g. an aircraft wing or a wind turbine blade, etc.) moving through the air typically has a condition of mainly turbulent air flow over the main part of the airfoil. The limited amount of laminar flow over wings and other aerodynamic surfaces, including a fuselage, is limiting the aerodynamic efficiency and fuel efficiency of current aircraft and the efficiency of a wind power station. Prior art aerodynamic surfaces are not designed and manufactured to the level of accuracy which is needed for laminar flow over a significant area (depending on the application, different for aircraft wing than for turbine blade) of these surfaces. It is known that a plasma field can improve the laminar flow over aerodynamic surfaces. However, known techniques present solutions where the plasma actuators have a limited efficiency and are not suited for a robust system with precise control management.
Natural laminar flow (NLF) of air over a wing or other aerodynamic surfaces will reduce drag, improve lift and improve the efficiency of the air foil. NLF is normally achieved by having a very accurate and smooth wing profile, which is fabricated in such way that it has significantly less geometrical steps, gaps and other deviations, e.g. waviness, than normally used technologies.
NLF can be achieved at certain airflow speeds and with certain wing profile configurations. It is more difficult to achieve at high speed and with swept wings due to cross flow over such wings.
US 2009/0212164 discloses improvement of the laminar flow over an aerodynamic surface using plasma generators comprising electrodes made of copper strips coupled to a control unit.
US 2009/0173837 discloses improvement of the laminar flow over an aerodynamic surface using plasma generators comprising electrodes including stainless steel.
Similar solutions have been experimentally verified but commercial use of these technologies is very limited or non-existing today, primarily due to lacking efficiency of the plasma generators based on existing technology and costly manufacture of the airfoil skin that would have to be fabricated to a very high surface quality.
Nano structure technology (such as nano fibres/tubes in polymeric materials) is an emerging technology of interest to the aircraft and windpower industry.
US 2006/0038087 discloses a system for augmenting the apparent velocity and effectiveness of an airfoil including electrodes made of nano tubes, wherein some of the electrodes are positioned on or above the upper surface of the airfoil.
It is desirable to provide a robust plasma-enhanced active laminar flow actuator system which improves the aerodynamic efficiency and which is energy efficient. It is also desirable to provide a product layer for the active laminar flow actuator system, which is cost-effective to produce and apply to an airfoil already in use or under development.
It is further desirable to provide a product layer for the active laminar flow actuator system which has an aerodynamic surface which is hard (erosion resistant) and ageing resistant.
An objective is also to eliminate drawbacks of known techniques, develop them and improve the application of the active laminar flow product layer in a robust system.